Armenia-Iran vs. Azerbaijan-Israel: Where is Russia?

The South Caucasus region has been seeing polarization as Armenia-Iran vs. Azerbaijan-Israel. The visits by Israeli PM Benjamin Netanyahu to Baku, Azerbaijan, and Iranian President Hassan Rouhani to Yerevan, Armenia in December, 2016 are indicative of the polarization. Where is Russia, the elephant in the room? What are the implications of the polarization for Russia?